Hemochromatosis is a common genetic disorder of iron metabolism that leads to cirrhosis, diabetes and cardiomyopathy. Early diagnosis and treatment with phlebotomy prevents these sequelae. Many investigators have advocated screening of the population with serum iron studies to identify presymptomatic individuals. Liver biopsy, however, is necessary to make the diagnosis. Identification of the gene would permit definitive diagnosis without liver biopsy. The disease is inherited in an autosomal recessive pattern and the gene has been localized near the HLA region on the short arm of chromosome 6. This grant application is a proposal to identify and map hemochromatosis candidate genes from the distal region of the hemochromatosis critical region. Using genomic clones such as Yeast Artificial Chromosomes (YACs), genes will be identified by cDNA hybridization selection. These genes as well as polymorphic markers will be hybridized back to digested YACs in order to generate a transcription map of the region. Based on genetic mapping of the hemochromatosis locus, candidate genes can then be analyzed for mutations in affected individuals, eventually leading to the identification of the gene responsible for hemochromatosis.